In existing storage systems with multiple storage controllers, at any given time, for every logical block address served by the system, there exist one or more controllers responsible for controlling access and managing writes to that address.
Hosts write data to the system via the storage controllers. The controllers control read and write access to the data. Logical data locations may reside in different physical locations within a shared storage space in the system. The controllers decide on the placement of data within the shared storage space, and maintain mapping information between logical addresses and physical addresses.